The present invention is drawn to ink-jet ink systems and methods for black and color printing with substantially reduced black to color bleed.
In recent years, computer printer technology has evolved to a point where very high resolution images can be transferred to various types of media, including paper. One particular type of printing involves the placement of small drops of a fluid ink onto a media surface in response to a digital signal. Typically, the fluid ink is placed or jetted onto the surface without physical contact between the printing device and the surface.
Properties that are desirable for black ink-jet ink compositions, to effectively compete with other imaging technology include neutral black color, neutral gray scale, and good optical density, and when printed with color inks, substantially reduced black to color bleed. Thus, with respect to black ink-jet inks, there is a challenge that exists related to maintaining light fastness, optical density, color neutrality, gray scale quality, and pen performance, while at the same time reducing black to color bleed when printed in conjunction other color dye-based inks. Thus, many have focused on the color ink-jet inks, rather than the black ink-jet inks, for reducing black to color bleed.
Several prior bleed control solutions have been implemented from reactive and non-reactive inks. For reactive pigment-containing black inks, black to color bleed control has been achieved by using salts in the color inks, such as, CaNO3 and MgNO3 to crash the pigment based black inks on the paper, thus forming a barrier that prevents bleed. Low pH color inks have also been used to crash the pigment based black inks.
For non-reactive dye-containing black inks, the available technique is to use surfactants in the black ink to control black to color bleed. The use of surfactants in the black ink has its drawbacks, in that the optical density of the black for the same amount of dye is reduced considerably by the use of surfactants. The spreading effect of surfactants also have a negative effect on print quality.
Illustrative of the art related to reducing bleed of ink-jet inks include the following. In U.S. Pat. Nos. 5,106,416, 5,116,409 and 5,133,803, it is disclosed that surfactants are effectively used to reduce bleed in dye-based ink formulations
Based upon the state of the prior art, improvement in the area of preventing bleed is desired. Specifically, it would be desirable to provide compositions, systems, and methods for reducing black to color bleed, without the necessity of including undesirable additives in the ink-jet ink formulations. Such compositions, systems, and methods are disclosed herein.
The present invention is drawn to compositions, systems, and methods for printing with reduced black to color bleed. Specifically, a method for printing black and color images with reduced black to color bleed is disclosed comprising the steps of providing a dye-based color ink-jet ink; providing a dye-based black ink-jet ink comprising at least one long chain alcohol in a glycol ether; jetting the dye-based color ink-jet ink onto a substrate; and jetting the dye-based black ink-jet ink onto the substrate, such that the dye-based color ink-jet ink contacts the dye-based black ink-jet ink at an interface, and substantially no color to black bleed occurs at the interface.
Additionally, a system for color printing with reduced black to color bleed is disclosed comprising an ink-jet pen containing a dye-based color ink-jet ink, wherein the ink-jet pen is capable of printing the color ink-jet ink onto a substrate; and an ink-jet pen containing a dye-based black ink-jet ink, wherein the black ink-jet ink comprises at least one long chain alcohol in a glycol ether; and wherein the ink-jet pen is capable of printing its contents on the substrate such that the black ink-jet ink contacts the color ink-jet ink. When the color ink-jet ink contacts the black ink-jet ink on the substrate at an interface, substantially no black to color bleed is present.
Further, a printed image on a substrate having reduced black to color bleed is disclosed. This printed image comprises a black ink-jet ink comprising at least one long chain alcohol in a glycol ether, printed in contact with a dye-based color ink-jet ink having substantially no bleed control treatment additives present.
Before the present invention is disclosed and described, it is to be understood that this invention is not limited to the particular process steps and materials disclosed herein because such process steps and materials may vary somewhat. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only. The terms are not intended to be limiting because the scope of the present invention is intended to be limited only by the appended claims and equivalents thereof.
It must be noted that, as used in this specification and the appended claims, the singular forms xe2x80x9ca,xe2x80x9d xe2x80x9can,xe2x80x9d and xe2x80x9cthexe2x80x9d include plural referents unless the content clearly dictates otherwise.
xe2x80x9cBlack to color bleedxe2x80x9d or xe2x80x9cbleedxe2x80x9d is defined as the undesirable intermixing of two or more ink-jet inks at a color-black interface, reducing the sharpness of the image. Bleed is particularly known to occur on fibrous papers, though it can occur on any substrate.
xe2x80x9cBleed control agentsxe2x80x9d or xe2x80x9cadditivesxe2x80x9d include any organic or inorganic substance added to ink-jet ink formulations in order to reduce bleed between colors or between black and a color on a substrate.
xe2x80x9cDye-based color inksxe2x80x9d or xe2x80x9cdye-based ink-jet inksxe2x80x9d used in the context of the present invention are essentially soluble.
Bleed control between non-reactive black and color inks has been achieved through a new technique. A combination of long chain alcohol, such as dodecanol or 1,2 decanediol, and a glycol ether improves black to color bleed without using large amounts of surfactants as penetrants. This allows bleed control without sacrificing optical density of the black inks. The optical density suffers when bleed control surfactants are used.
The present invention enables a work group printer, which typically requires high optical density and good print quality output, to utilize a color ink-jet ink and a black ink-jet ink neither of which contains bleed control surfactants. In the case of black ink-jet ink, these additives have a significant negative effect on optical density. Furthermore, the spreading effect of surfactants has a generally negative effect on print quality in both black and color ink-jet ink. Thus, the present invention provides very good black to color bleed control without the use of these traditional additives.
With this in mind, the present invention is specifically drawn to compositions and methods for printing color images with reduced black to color bleed.
The inventor in the present application has discovered that by combining higher alcohols that are sparingly soluble in water with glycol ethers that dissolve the alcohols, a solution is created which is soluble in water. In a preferred embodiment, the glycol ethers are present in a range from 0.1 to 15 wt %.
When this solution is added to the dye-based black and color inks, black to color bleed is controlled without the negative effects of surfactants, which include reduced optical density in dye-based black ink and decreased print quality in both black and color dye-based ink.
This prevention of black to color bleed comes about as follows: The ejected drop hits the paper. Ink paper interaction causes the sparingly soluble alcohols to separate from the bulk ink and go to the interface between the dye-based black and the dye-based color inks. The alcohols therefore prevent black to color bleed by this separating out and moving to the interface.
A method of the present invention comprises the steps of providing a dye-based color ink-jet ink comprising at least one long chain alcohol in a glycol ether; providing a dye-based black ink-jet ink comprising at least one long chain diol in a alcohol ether; jetting the dye-based color ink-jet ink onto a substrate; and jetting the dye-based black ink-jet ink onto the substrate. When these steps are followed such that the dye-based color ink-jet ink contacts the dye-based black ink at an interface, substantially no color to black bleed occurs at the interface.
Additionally, a system for color printing with reduced black to color bleed is disclosed comprising a first ink-jet pen containing a dye-based color ink-jet ink comprising at least one long chain alcohol in a glycol ether; that is capable of printing the color ink-jet ink onto a substrate. Next, a second ink-jet pen containing a dye-based black ink-jet ink is present comprising at least one long chain alcohol in a glycol ether. The second ink-jet pen should be configured such that the black ink-jet ink can contact the color ink-jet ink once printed on the substrate. Thus, when the color ink-jet ink contacts the black ink-jet ink on the substrate, substantially no black to color bleed is occurs at a black-color interface.
Next, a printed image on a substrate is disclosed having reduced black to color bleed. The printed image comprises a dye-based black ink-jet ink comprising at least one long chain diol in a glycol ether. The dye based black ink-jet ink is printed in contact with, a dye-based color ink-jet ink comprising at least one long chain alcohol in a glycol ether. Even without traditional bleed control agents in the color ink-jet ink, by using the black ink-jet inks disclosed herein, substantially no black to color bleed occurs.